ran my hemi hard today, she did NOT like it

[LNDRCKT]

It sounds like you got into the upper rpm range on the intake manifold. There is a door inside the intake that switches the runner length at around 3500. It does make a different sound on the intake side when that happens. If you never get into that rpm range then maybe the door was stuck and it didn’t fully engage.

 

[My1stHemi]

Did you notice any soot blowing out? Sounds like an Italian tune-up as a former employer used to say. That was his trick for old Fiats and Alpha Romeos. Car runs rough from carbon build up, so you go flog it for a bit to blow out the crud.
My dad had an audi allroad with a the 2.7l twin turbo v6. Super fun car but be drove it like a grandma because it was his first nice car. It started running like crap under warranty and the dealer had to remove carbon deposits from the valves. Technician said to run it hard at least once a week to blow out the cobwebs.
I spoke with a shop manager at an MB dealer in the bay area once that sold a ton of AMG cars to trophy wives who used their 500hp cars to drive to yoga and the mall. Same problem.

 

[Reverse]

I had the same hing happen on my 4th gen. Happened only when really getting on it (passing etc.), but not every time. Sort of a hard whooshing/crackle sound, like an exhaust or manifold leak. Scared the crap out of me the first time it happened. Didn't seem to hurt the truck though. My wife still drives it every day with 170,000+ miles on it now I believe.

 

[Aseras]

Make sure your using Top Tier fuel. I think that's more important than what octane u put in. Speedway & Sam's Club do NOT sell Top Tier fuel. Most other big name gas stations do. Google top tier fuel & they have a list on their website of which gas stations sell it. There should also be a label on the pump. Costco sells Top Tier. So does Holiday.

The fuel trucks get their gas all at the same place. Its the same gas. Just a different additive package tossed in during fill. Top tier is a marketing gimmick. Ethanol free is not and is a much better quality gas as the additoves it needs are much better than cheap ethanol to keep water out and stabilize it.

 

[PowerJrod]

I'm kinda worried about the ole girl. I was getting onto the freeway and there was a short onramp and lots of traffic so I leaned into it pretty hard and fast. It revved up and downshifted as normal, but it really made a loud crackling noise for a few seconds while it was at 3000 to 5000 rpms (also I think it might have lost a bit of power while it was crackling away); went away the instant I got off the throttle and it upshifted. Back to smooth hemi sound.

Later in the trip I gave it a bit a few times, but not as hard, and sound didn't come back? Sounded like a well running hemi should.

No codes anywhere on the dash, but I will swear that was NOT normal. It sounded like I lost my exhaust for a few seconds?? But the sound was definitely "out front" under the hood, it was not a sound coming from behind. Freaked me out, never heard that before.

Anybody have any ideas?

Did you leave a bag of popcorn seeds under the hood?

 

[PowerJrod]

The fuel trucks get their gas all at the same place. Its the same gas. Just a different additive package tossed in during fill. Top tier is a marketing gimmick. Ethanol free is not and is a much better quality gas as the additoves it needs are much better than cheap ethanol to keep water out and stabilize it.

Not even close dude....
Modern engines are not designed to run on Ethanol Free gas. Plus...top tier gas is refined a different way than others before it hits the trucks. Learn more about it before you BS people on here please.

 

[Rsorrell2]

PowerJrod I agree with you that top tier gas has additional additives but not that “Modern engines are not designed to run on Ethanol Free gas”.

if you check the onwers manual and your gas door it states that it does not want E85 which is 15% ethanol. I have found and used ethanol free gas and my truck ran much better and I got better MPG with ethanol free.

 

[STIG302]

I also agree. My truck runs better on ethanol free gas when I can get it. All you need to do is to meet the OEM requirement for additives and you can be Top Tier. Costco’s Top Tier has six times the additives of the minimum recommended by OEM. And it is the cheapest gas around. All around excellent value. When you use an 87 octane that is Top Tier versus an 87 octane that isn’t, there’s no difference in performance. Top Tier is an additive for preventing carbon buildup and cleaning injectors. It isn’t octane. Octane will boost performance. And no, I don’t work for Costco.


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[UnloosedChewtoy]

if you check the onwers manual and your gas door it states that it does not want E85 which is 15% ethanol. I have found and used ethanol free gas and my truck ran much better and I got better MPG with ethanol free.

I completely agree with you on the ethanol free = better MPG, experienced it myself many times with the Hemi.

However, E85 is not 15% ethanol, its 85% ethanol. E10 is 10% ethanol, E15 is 15% ethanol, etc. although they do not use the E10/E15/etc. names for the smaller ethanol numbers as frequently.

E85 - Wikipedia

en.wikipedia.org

 

[Slumlord]

Thanks everyone for your comments. I ran 91 because the manual says 89 is recommended and I thought I'd "treat" her well since gas prices are so low. I had problems with pinging when using 87 octane at the same pump, the pinging goes away mostly with 89, but everybody fills up with 87 so then the first bit of gas you get is 87 even when you select 91, it's left over in the hose. So the theory is... if you put 89 in, but the first eigth is left over in the hose at 87 octane, then I'm not getting a full tank of true 89. Using 91 should have no trouble reaching 90 to 90.5 octane. Maybe I'm just being stupid with the hose thing, who knows.

I was also under the (apparently mistaken) impression that 0 ethanol was best for our trucks? This pump has been reported on a website to supply 0 ethanol, again, just ran it to help the truck run the best it can.

I was pretty much WOT, but it wasn't hitting the rev limiter. It did it under very hard acceleration, going to say from memory, somewhere between 3000 to 5000 rpms. So it was an entire RPM range that it made the sound under.

Guess there is nothing else to be done but drive it hard for a while, see if I can reproduce.

You are actually losing power by running non-ethanol. Newer engines are desinged to use ethanol. On my 2016 Camaro SS they actually sold ethanol kits that you could install that would give you 30-40 HP from using e-85.

 

[PowerJrod]

PowerJrod I agree with you that top tier gas has additional additives but not that “Modern engines are not designed to run on Ethanol Free gas”.

if you check the onwers manual and your gas door it states that it does not want E85 which is 15% ethanol. I have found and used ethanol free gas and my truck ran much better and I got better MPG with ethanol free.

Really??? I was told that Ethanol Free gas can damage the engine over time...I have a station next to where I work that has Ethanol Free and I wanted to try it but then I heard that it's not something that our trucks should be using.

 

[SD Rebel]

Really??? I was told that Ethanol Free gas can damage the engine over time...I have a station next to where I work that has Ethanol Free and I wanted to try it but then I heard that it's not something that our trucks should be using.

I've always heard the opposite, especially for older engines. Ethanol free is preferred, but modern engines are designed to tolerate higher levels of Ethanol like E15. But most older engines can't do higher than E10, and almost all motorcycles and small engines E10 is the max.

Our RAMs fuel ethanol range is 0% - 15%. So up to E15 max, definitely no on E85, which is 85% ethanol. The less ethanol, the better your mpg.

 

[Kidder]

Really??? I was told that Ethanol Free gas can damage the engine over time...I have a station next to where I work that has Ethanol Free and I wanted to try it but then I heard that it's not something that our trucks should be using.

This is absolutely wrong. Ethanol Free is the way to go if you can find it. It is better for the engine and you should get better MPG.

 

[silver billet]

You are actually losing power by running non-ethanol. Newer engines are desinged to use ethanol. On my 2016 Camaro SS they actually sold ethanol kits that you could install that would give you 30-40 HP from using e-85.

Ethanol does give more power, but you lose MPG. "Designed" is not the word I would use when talking about the Hemi. The 3.6 Pentastar, yes, that runs on flex fuel/E85, but the Hemi merely tolerates low doses.

 

[Scram1500]

The engine doesn't really care, is all the o-rings and rubber hoses that can't tolerate alcohols

 

[STIG302]

The engine doesn't really care, is all the o-rings and rubber hoses that can't tolerate alcohols

You nailed it.


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[Jako]

Ethanol does give more power, but you lose MPG. "Designed" is not the word I would use when talking about the Hemi. The 3.6 Pentastar, yes, that runs on flex fuel/E85, but the Hemi merely tolerates low doses.

My understanding is ethanol increases octane and has less energy. Not sure what you mean by more power and less MPG.

Optimal gas to use here in the US? Octane vs Ethanol?

www.124spider.org

Ethanol

Ethanol is a renewable, domestically produced alcohol fuel that can help reduce oil dependence and greenhouse gas emissions.

fueleconomy.gov

"Ethanol contains about one-third less energy than gasoline. So, vehicles will typically go 3% to 4% fewer miles per gallon on E10 and 4% to 5% fewer on E15 than on 100% gasoline.3"

 

[UnloosedChewtoy]

Running 10% or maybe even 15% ethanol will not damage a modern engine.
Running ethanol free gas will not damage a modern engine.
Running any ethanol in an older engine may damage seals/gaskets/etc. that were not designed to take it. I do not know exactly where the cut-off is, but definitely pre-5.7 Hemi.

I would love to see the science/evidence behind the argument that running ethanol free gas will damage an engine.

Higher compression engines and/or engines tuned for ethanol can get more power from it compared to gasoline due to the higher octane of ethanol. Hence why you read about many race-type cars using it.
However, it takes more volume of fuel to get to that power, due to ethanol having less energy per unit.
Therefore ethanol will always net you less MPG. In a short-duration race situation, no one cares about MPG, hence why you'll see it used there by many.

Without heavy computer/tune modifications, if not other mods, ethanol free gas on a 5.7 Hemi will get you better power and better MPG. Period.
However, we are not talking crazy gains vs E10/E15. As others have stated, a couple MPG (ish) typically in the case of our 5.7 engines seems to be the average.

 

[PowerJrod]

I've always heard the opposite, especially for older engines. Ethanol free is preferred, but modern engines are designed to tolerate higher levels of Ethanol like E15. But most older engines can't do higher than E10, and almost all motorcycles and small engines E10 is the max.

Our RAMs fuel ethanol range is 0% - 15%. So up to E15 max, definitely no on E85, which is 85% ethanol. The less ethanol, the better your mpg.

View attachment 65743

Huh...might be worth a try then. Maybe I'll try a few gallons of it mixed with what I already have in the tank. I don't remember seeing an octane rating on the E-Free gas though....

 

[SD Rebel]

Huh...might be worth a try then. Maybe I'll try a few gallons of it mixed with what I already have in the tank. I don't remember seeing an octane rating on the E-Free gas though....

Depends where you live, in my area its impossible to find non-ethanol fuel unless you get 100 octane race gas which isn't ideal for regular vehicles.

Also aviation fuel and some boat fuel sites may have it. Different states will probably have more of it available in regular grades than the Republic of California.